Buggy code:
public class WikiMarkup extends Parser { private final StringBuilder lineBuffer ; private ArrayList < WikiMarkup . MarkupStart > lineMarkup ; private ArrayList < TextNode > parentList ; private int inlineFragmentIndex ; private boolean inlineWhitespaceConsumed ; private int openTemplates ; private WikiMarkup . MarkupStart previousMarkup ; private WikiMarkup . SymbolType [ ] symbolLut ; private static class MarkupStart { public enum MarkupType { START , END , NONE ; } public WikiMarkup . SymbolType symbol ; public String sourceLocation ; public int location ; public int count ; public WikiMarkup . MarkupStart matchingMarkup ; public WikiMarkup . MarkupStart . MarkupType type ; } private static class SymbolType { public char character ; public boolean multiple ; public boolean end ; public int priority ; public SymbolType ( char character , boolean multiple , int priority , boolean end ) { } public SymbolType ( char character , boolean multiple , int priority ) { } } public WikiMarkup ( ) { } private void printDebug ( String str ) { } private void printDebug ( String str , boolean newline ) { } private TextNode getCurrentFragment ( ) { } private void closePreviousFragment ( ) { } private void itemListTruncate ( int newSize ) { } public void createSymbolLut ( ) { } public boolean parse ( Reader reader ) throws IOException { } public TextNode getRoot ( ) { } private void parseLine ( ) { } private void parseLineStartMarkup ( ) { } private void createParagraphIfNeaded ( ) { } private void parseRuler ( ) { } private void parseTable ( ) { } private WikiMarkup . MarkupStart createHeaderNode ( ) { } private void parseInlineMarkup ( ) { } private WikiMarkup . MarkupStart appendMarkupStart ( WikiMarkup . SymbolType symbol ) { } private void handleInlineMarkup ( WikiMarkup . SymbolType symbol ) { } private void parseListItem ( ) { } private void createList ( String parameter ) { } private void createListItem ( int type ) { TextNode item ; TextNode list ; list = getCurrentFragment ( ) ; if ( ( ( ( list . getType ( ) ) == ( TextNode . LIST_ITEM_TYPE ) ) || ( ( list . getType ( ) ) == ( TextNode . DEFINITION_ITEM_TYPE ) ) ) || ( ( list . getType ( ) ) == ( TextNode . DEFINITION_LABEL_TYPE ) ) ) { closePreviousFragment ( ) ; list = getCurrentFragment ( ) ; } if ( ( list . getType ( ) ) != ( TextNode . LIST_TYPE ) ) { <START_BUG> printDebug ( "ERROR:<seq2seq4repair_space>must<seq2seq4repair_space>be<seq2seq4repair_space>list" ) ; <END_BUG> } printDebug ( ( "New<seq2seq4repair_space>list<seq2seq4repair_space>item<seq2seq4repair_space>" + ( getSourceLocation ( ) ) ) ) ; item = new TextNode ( type ) ; list . appendChild ( item ) ; parentList . add ( item ) ; } private void createParagraph ( ) { } private int getNextMarkupSymbolIndex ( WikiMarkup . SymbolType symbol , int startIndex ) { } private WikiMarkup . MarkupStart getMarkupSymbol ( WikiMarkup . SymbolType symbol ) { } private void handlePreviousMarkup ( ) { } private void handleMarkup ( WikiMarkup . MarkupStart markup , WikiMarkup . MarkupStart previousMarkup ) { } private void createTextNode ( WikiMarkup . MarkupStart markup , WikiMarkup . MarkupStart previousMarkup ) { } private void parseHeaderMarkupStart ( ) { } private void appendInlineTextNode ( int type ) { } private void createMarkupStart ( WikiMarkup . MarkupStart start , WikiMarkup . MarkupStart end ) { } private void createTextStyleMarkup ( WikiMarkup . MarkupStart end ) { } private void handleTextStyleMarkup ( WikiMarkup . MarkupStart markup ) { } private void createLinkMarkup ( WikiMarkup . MarkupStart end ) { } private void createLinkNode ( WikiMarkup . MarkupStart start ) { } private void endLinkNode ( WikiMarkup . MarkupStart end ) { } private void createTemplateMarkup ( WikiMarkup . MarkupStart end ) { } private void createTemplateNode ( WikiMarkup . MarkupStart start ) { } private void endTemplateNode ( WikiMarkup . MarkupStart end ) { } private void createHeaderMarkup ( WikiMarkup . MarkupStart end ) { } }

Fix:
throw new Error ( "ERROR:<seq2seq4repair_space>must<seq2seq4repair_space>be<seq2seq4repair_space>list" ) ;